Tadeu José da Silva Peixoto Sobrinho

Levels of Tannins and Flavonoids in Medicinal Plants: Evaluating Bioprospecting Strategies

There are several species of plants used by traditional communities in the Brazilian semiarid. An approach used in the search for natural substances that possess therapeutic value is ethnobotany or ethnopharmacology. Active substances that have phenolic groups in their structure have great pharmacological potential. To establish a quantitative relationship between the species popularly considered to be antimicrobial, antidiabetic, and antidiarrheal, the contents of tannins and flavonoids were determined. The plant selection was based on an ethnobotanical survey conducted in a community located in the municipality of Altinho, northeastern Brazil. For determination of tannin content was utilized the technique of radial diffusion, and for flavonoids, an assay based on the complexation of aluminum chloride. The group of plants with antimicrobial indications showed a higher content of tannins compared to the control groups. The results evidence suggests a possible relationship between these compounds and the observed activity.

Antioxidant Capacity and Phenolic Content of Caesalpinia pyramidalis Tul. and Sapium glandulosum (L.) Morong from Northeastern Brazil

The aims of this study were to quantify the phenolic content and evaluate the antioxidant potential of extracts from the bark and leaves of C. pyramidalis and S. glandulosum. The total phenolic content (TPC) and total tannin content (TTC) were determined using the Folin-Ciocalteu method, and the total flavonoids content (TFC) was measured via complexation with aluminum chloride. The antioxidant activity was evaluated with DPPH (2.2-diphenyl-1-picrylhydrazyl) and FIC (ferrous ion chelating) assays. The TPC ranged between 135.55 ± 9.85 and 459.79 ± 11.65 tannic acid equivalents (TAE) in mg/g material (mg TAE/g). The leaves of both species contained high levels of tannins and flavonoids. The crude ethanol extracts (CEE) from the bark of C. pyramidalis showed high antioxidant activity when compared to ascorbic acid and rutin, whereas the CEE from the leaves was more efficient in chelating ferrous ions. C. pyramidalis had very high phenolic content and anti-radical activity, which indicates a need for further studies aimed at the purification and identification of compounds responsible for the antioxidant activity.

Análise da pluviosidade e do efeito de borda sobre os teores de flavonóides em Bauhinia cheilantha (Bong.) Steud., Fabaceae

The present study evaluated the influence of the edge-effect and rainfall on flavonoid content in individuals of Bauhinia cheilantha (Bong.) Steud., Fabaceae, in an area of caatinga vegetation in Pernambuco State, northeastern Brazil. The analytical methodology used aluminum chloride binding to quantify flavonoid concentrations by visible light spectrophotometry in leaf extracts of B. cheilantha. In general, forest edges influenced flavonoid production, but it was not possible to relate production with rainfall levels. These results demonstrate that this species uses various strategies to respond to environmental variables.

Standard Operating Procedures (SOP) for the Spectrophotometric Determination of Phenolic Compounds Contained in Plant Samples

The quality control of raw materials and products from plants is one of the topics most discussed by universities and health surveillance agencies. One of the primary tools used to ensure the reliability of production processes is the use of Standard Operating Procedures (SOPs). SOPs sequentially describe the steps of a particular methodology so that it can be reproduced by different analysts, which minimises variations in their implementation and improves the standardisation of the final product.

Evaluation of antibacterial activity of the bark and leaf extracts of Brosimum gaudichaudii Trécul against multidrug resistant strains

Abstract Brosimum gaudichaudii Trécul., a plant that belongs to Moraceae family, is found throughout the Brazilian Cerrado. The antimicrobial activities of ethanolic bark and leaf extracts of B. gaudichaudii were tested against multiresistant bacteria isolated from diabetic foot infections (DFIs). Antimicrobial activity of the extracts was evaluated by agar disc diffusion (DD) and broth dilution (BD) methods. By BD method, bark (53.85, 45.83%) and leaf (42.31, 50.00%) extracts contained antimicrobial activity against both gram-negative and gram-positive bacteria. Increased antimicrobial activity was observed when bark and leaf extracts were tested against Staphylococcus aureus (63.64%) and Pseudomonas aeruginosa (66.67%). Statistical analyses of bark and leaf extract demonstrated antimicrobial activity against both gram-positive (p = 0.000) and gram-negative bacteria (p = 0.012). Extract of bark (p = 0.075) or leaf (p = 0.005) associated with ACA antibiotic showed antimicrobial activity against gram-positive bacteria. Our study suggests that the bark and leaf extracts contain bioactive compounds with antimicrobial activity against multidrug resistant strains.

The Anticholinesterase Properties of Plants from the Northeast of Brazil Selected by an Ethnopharmacological Study for Disorders Relating to the Nervous System.

Background: Various factors may trigger Alzheimers disease and the cholinergic hypothesis, which is one of the most widely accepted, argues damage to the brain nuclei, may reduce the production of the choline acetyltransferase enzyme, and cause a decline in the synthesis of acetylcholine (ACh). Studies have thus focused on discovering molecules that are capable of inhibiting the action of cholinesterase enzymes that degrade ACh, thereby preventing the evolution of the disease. Objective: The aim of the present study is to assess the anticholinesterase properties of extracts of medicinal plants in a semi-arid region of Northeast of Brazil. Materials and Methods: The species were selected by way of an ethnobotanical study and were collected if there were some indications that they are related to the nervous system. The plant samples were extracted using hexane, ethyl acetate, and methanol. Anticholinesterase activity in vitro was assessed by way of bioautography in thin layer chromatography and microassays in 96-well plates. Results: Twenty-three species of plant were collected, and 75 extracts were analyzed. The bioautography revealed that 26.7% of the samples showed inhibitory activity against the acetylcholinesterase (AChE) enzyme. After the test for false positives, 8% of the samples were found to inhibit AChE. Thirty samples were analyzed by microassay (500 μg/mL), on which 86.7% showed moderate to powerful anticholinesterase activity. Conclusion: Of the extracts tested, Citrus limonum, Ricinus communis, and Senna occidentalis stand out as was the most promising in terms of anticholinesterase activity and may serve as a guide for the discovery and development of new substances for the treatment of AD. SUMMARY The bioautography revealed that 26.7% of the samples showed inhibitory activity against the acetylcholinesterase enzyme Samples were analyzed by microassay (500 μg/mL), upon which 86.7% showed moderate to powerful anticholinesterase activity Citrus limonum, Ricinus communis, and Senna occidentalis stand out as being the most promising in terms of anticholinesterase activity C. limonum, R. communis, and S. occidentalis may serve as a guide for the discovery and development of new substances for the treatment of Alzheimers disease. Abbreviations used: AChE: Acetilcolinesterase Valerium Thijan Nobre de Almeida e Castro